A psychiatrist said that one of the top risks to adolescent health is "developing hallucinations and psychosis from the use of marijuana."

"If this psychosis risk was limited to only a few days reaction after last cannabis use, it would be far less frightening, but this instead can involve the development of longer-term psychosis, or schizophrenia," Dr. Robert J. Hilt an associate professor of psychiatry at the University of Washington and Seattle Children's Hospital, wrote in the March issue of the Pediatric Annals journal.

A Curtis High School senior told the Advance he started smoking weed nearly every day when he was a freshman.

"My grades when from B's to D's and F's, but I didn't care," he said. "I was cutting just to cop and get high."

He said his parents grounded him, but it didn't matter. Then, he said, he "stopped having fun and almost got arrested."

"About a year ago, it started making me paranoid, so I stopped,'' he said.

His friend, a junior from West Brighton, said he still smokes, "but only on weekends."

He said he can't smoke during the week "because doing math is impossible."

When
asked about the possible effect pot smoking might have on their future
intellectual development and mental health, both shrugged.

"Good times,'' said the junior. "We'll be fine.''

Dr. Hilt's article landed amid a national conversation about recreational marijuana use and the legalization of medical marijuana.

Citing multiple studies, Dr. Hilt said that pot smokers who developed schizophrenia had a significantly earlier age of onset of symptoms than non-users.

He acknowledged that teens with "pre-psychotic symptoms like social withdrawal could for some other undefined reason be preferring to recreate by using marijuana over any other drugs of abuse just before developing their overt psychosis."

But based on his own observations of teens who develop long-term psychosis without any signs of having such risks before using pot, Dr. Hilt said, "the 'it is just a coincidence' explanation to me is unsatisfactory."

Dr. Hilt said that the adolescent brain "is not the same as the adult brain" in terms of information processing, numbers of neurons and other factors.

"Anything that disrupts normal brain development, connection, and pruning processes in adolescence can understandably have lasting effects," he said, including marijuana use.

Sarah Anderson, program director for Treatment Alternatives for Safer Communities in Stapleton, said that pot does have "psycho-active properties."

She said that some teens who use the synthetic marijuana known as K2 have been sent to mental hospitals for treatment.

"There have definitely been personality changes," she said.

And Ms. Anderson added that in her experience, some people with mental health issues tend to use marijuana as a "drug of choice" when self-medicating.

In 2010, neurologist Frances Jensen told NPR that a teen who smokes pot will still show cognitive deficits days later. Adults return to the cognitive baseline much faster, she said.

Dr. Hilt said that he tells his adolescent patients that they have an "age-related risk of developing long-term hallucinations or schizophrenia from abusing marijuana, which tends to get their attention."

"Thankfully," he added, "most adolescents who abuse marijuana do not become psychotic adults."

Opinion is split on whether youthful pot use causes psychosis later in life.

A 2013 Harvard University study concluded that a familial morbid risk of schizophrenia may be the underlying basis for schizophrenia in cannabis users, and not cannabis use by itself.